Which of the following drugs is an inhibitor of platelet glycoprotein IIb/IIIa receptors?

Correct Answer: D

Rationale: The correct answer is D: Abciximab. Abciximab is a glycoprotein IIb/IIIa receptor inhibitor, which prevents platelet aggregation. It works by binding to the receptor and blocking the final common pathway of platelet aggregation. Aspirin (A) inhibits cyclooxygenase, Clopidogrel (B) and Ticlopidine (C) are P2Y12 ADP receptor inhibitors, not glycoprotein IIb/IIIa inhibitors. Abciximab (D) is the only drug among the choices that directly targets the glycoprotein IIb/IIIa receptors on platelets, making it the correct answer.

Correct Answer: C

Rationale: Rationale for the correct answer (C - Enalapril): 1. Enalapril is a prodrug that requires conversion to its active form, enalaprilat, in the liver. 2. Enalaprilat has potent ACE inhibitory effects, making it the active metabolite responsible for the drug's therapeutic action. 3. The conversion process enhances the drug's bioavailability and ensures a consistent pharmacological response. Summary of why other choices are incorrect: A: Labetalol is not converted to an active metabolite after absorption; it exerts its effects directly. B: Clonidine acts directly on alpha-2 adrenergic receptors without requiring conversion to an active form. D: Nifedipine is a calcium channel blocker that does not need metabolic activation for its pharmacological effects.

Correct Answer: C

Rationale: The correct answer is C: Growth hormone. The posterior pituitary gland only secretes Vasopressin (A) and Oxytocin (B). Growth hormone (C) is actually secreted by the anterior pituitary gland. Therefore, option C is incorrect. Option D is also incorrect as the posterior pituitary does secrete Vasopressin and Oxytocin.

Correct Answer: D

Rationale: Step-by-step rationale for why choice D is correct: 1. Biguanides like metformin are not used in hyperglycemic shock due to their slower onset of action. 2. In hyperglycemic shock, rapid-acting medications like insulin are needed for immediate correction. 3. Choices A, B, and C are incorrect because biguanides are commonly used as an initial treatment for type 2 diabetes to improve insulin sensitivity and reduce glucose production in the liver.

Correct Answer: C

Rationale: The correct answer is C: Metamizole (Analgin). Metamizole is a pyrazolone derivative due to its chemical structure containing a pyrazolone ring. Ibuprofen (A) is a propionic acid derivative, Indomethacin (B) is an indole derivative, and Diclofenac (D) is a phenylacetic acid derivative. Pyrazolone derivatives like Metamizole are known for their analgesic, antipyretic, and anti-inflammatory properties.